What is Node js?

Koa.js is a web framework for Node.js that is designed to be smaller, more expressive, and more modular than other popular Node.js frameworks, such as Express.js. It was created by the team behind Express.js to address some of the limitations and shortcomings of the earlier framework.

One of the key features of Koa.js is its use of async functions, which makes it easier to write asynchronous code in a more elegant and concise manner. Koa.js uses the ‘async’ and ‘await’ keywords to handle asynchronous operations, such as I/O requests and database queries, without the need for callbacks or promises.

Express.js is a popular web framework for Node.js that provides a robust set of features for building web applications and APIs. It is designed to be flexible, scalable, and easy to use, making it a popular choice for both beginners and experienced developers.

One of the key features of Express.js is its middleware system. Middleware functions are functions that take the request and response objects, modify them in some way, and then pass them on to the next middleware function in the chain. This allows developers to add functionality to their application in a modular and extensible way, making it easier to write maintainable and scalable code.

Nest.js is a progressive Node.js framework for building scalable and modular server-side applications. It was inspired by Angular and uses a similar architecture, making it easy for developers who are familiar with Angular to pick up and use. One of the key features of Nest.js is its use of decorators to define modules, controllers, and services. This makes it easy to create a modular and extensible architecture, allowing developers to organise their code into reusable components.

Nest.js also provides a range of other features and functionality, including: Dependency injection, Middleware, Routing, as well as built-in support for WebSockets, OpenAPI and TypeScript. 

Hapi.js is a popular open-source framework for building web applications and APIs with Node.js. It was originally developed by Walmart Labs, and is designed to be modular, extensible, and developer-friendly. One of the key features of Hapi.js is its plugin architecture. Hapi.js provides a rich set of built-in plugins, such as authentication, validation, and caching, which can be easily integrated into an application. In addition, developers can create their own plugins and share them with the community.

Hapi.js is a powerful and flexible framework for building web applications and APIs with Node.js. Its modular and plugin-based architecture, along with its range of features and functionality, make it well-suited for building large-scale and complex applications.